﻿using System;
// 定义一类圆，求圆的周长和面积
namespace 第四题
{
    class circle
    { 
        public double R { get; set; }
        public circle() { }
        public circle(double R)
        {
            this.R = R;

        }
        public void Math()
        {
            Console.WriteLine("周长="+(2*R*3.14));
            Console.WriteLine("面积=" +(R*R * 3.14));
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            circle C = new circle();
            C.R =double.Parse( Console.ReadLine());
            C.Math();
        }
    }
}
